FR3106870A3 - Mechanical transmission - Google Patents

Abstract

The invention is a very simple and very rustic stepped mechanical transmission, the ratio of which varies manually or automatically, for example as a function of the torque transmitted or the speed of rotation of the input shaft or of the output shaft or a combination of these parameters. It can automatically select the most suitable transmission ratio and does not produce any acyclism. Such transmissions can also be used in the manufacture of robotic dual-clutch transmissions and transfer significant powers, while remaining very simple to manufacture and inexpensive. Fig. 1

Description

Mechanical transmission

The invention is a very simple and rustic mechanical transmission of design whose, in an improved version, the transmission ratio can vary automatically according to the torque to which it is subjected or the speed of rotation of its input shaft or of its output shaft, or even other parameters such as for example by order of an operator or a computer.

Technical problem

Many engineers have designed gearboxes that are manual or have automatic gearboxes. None are really satisfactory and all are expensive to manufacture and made fragile by their complex design.

We know a very large number of documents describing manual and automatic gearboxes.

We know in particular the application PCT-FR-2019-000030 by Franck Guigan [FR] filed on March 6, 2019, which proposes to use a mechanical means allowing the crank pin of a crank to approach its axis of rotation under the 'effect of a force created by the torque to which the transmission is subjected, and / or moving away from it by its speed and / or by an elastic return, which has the effect of varying the amplitude of the movement of and comes from a connecting rod driven by this crank pin and controlling by a freewheel the rotation of an output shaft always in the same direction.

We also know the documents cited by this application, those cited in its search report as well as those cited in the search report of patent application FR1870485 by Franck Guigan [FR] filed on April 24, 2018.

The invention will be well understood, and other objects, advantages and characteristics thereof will emerge more clearly on reading the description which follows, which is illustrated by FIGS. 1 to 12 which all represent devices or part of them. devices according to the invention.

To simplify the presentation,
- We will say hereafter that an elementary transmission is “connected” or “engaged” in the case where it drives its output shaft also called its output according to its transmission ratio, and that it is “disconnected” or “disengaged »In the opposite case;
- An “adjacent” elementary transmission will be called an elementary transmission having the transmission ratio closest to the elementary transmission considered, higher or lower than that of the transmission considered,
- and an elementary transmission will be defined by its "rank" in the list of elementary transmissions whose transmission ratio is increasing, starting from the elementary transmission of rank 1 for that corresponding to the lowest transmission ratio also commonly called the " first speed ”. Several adjacent elementary transmissions of increasing rank can thus be referred to as the “first speed”, the “second speed”, the “third speed”, etc.

is a perspective view of a transmission with three elementary transmissions according to the invention, the ratio of which changes as a function of the speed of rotation of the input shaft 2. It therefore has three speeds corresponding to three different transmission ratios . The input shaft 2 rotates three so-called input toothed gears of different diameters, of which only the largest can be seen 203. It drives the input gears in rotation by three limiters which are drive arms 403a 403b and 403c, one end of which pivots about an axis close to the axis of rotation of the input shaft 2 and the other of which cooperates with a stop 503 or 503b integral with the input pinion 203. Each pinion of input rotated by the input shaft 2 can in turn drive in rotation by gearing a toothed pinion said output driving the output shaft 3 by a freewheel. We see the freewheel 603 by which the output pinion 303 rotates the output shaft. The centrifugal force which is applied to the shafts tends to move them away from the axis of rotation of the input shaft 2, but an elastic return 803 tends on the contrary to bring the ends of these shafts closer to the axis of rotation of the input shaft 2. The tension of this elastic return is adjustable by the slider 804.

is a perspective view of a similar transmission, seen from the same side but from a different perspective. Input sprockets are not shown for viewing of all three drive arm assemblies. These drive arms are synchronized and all their ends are at the same distance from the axis of the input shaft 2.

is a perspective view from another angle of the same transmission, this time fitted with all its input gears.

is a perspective view of a drive arm synchronization mechanism 401a, 401b and 401c. Each of these three drive arms is integral with the corresponding drive arms associated with the other two input pinions.

is a perspective view of an improved transmission, one of the elementary transmissions of which has a variable transmission ratio, comprising a crank 101 connected by a connecting rod 106 to an engine lever 105 which is flexible. This first transmission with three elementary transmissions is associated in parallel with another transmission also comprising three elementary transmissions of different ratios, called odd ratios to differentiate them from the so-called even ratios of the first transmission. There are therefore six speeds, one of which has a variable transmission ratio. Each transmits its movement to a clutch disc, 801 for odd gears and 802 for even gears. A movable clutch disc 800 cooperates alternately with one and with the other to benefit from the advantages of a robotic dual-clutch transmission.

is a perspective view of a transmission, the elementary transmissions of which are engaged as a function of the torque transmitted. Unlike the transmissions of Figures 1 to 3 and 5, the elastic return 803 tends to move the ends of the shafts away from the axis of rotation of the input shaft 2, and the tension of this elastic return is adjustable by the slider 804. We can distinguish a helical spring 806 which allows the part of a toothed pinion comprising the teeth can angularly offset from the central part of this pinion causing the freewheel under the force of a torque transferred by the pinion, in order to reduce the shock imposed on the freewheel when this pinion begins to be driven.

is a perspective view of another transmission according to the invention, the elementary transmissions of which are also connected according to the torque transmitted. The drive arms are here inside the input pinions, and we see the stops 501a and 501b of the first gear, which drive the input pinion 201.

is a perspective view of the same transmission seen from another angle, but here stripped of its primary gears so that we can see the detail of the arms 401a 402a and 403a which can pivot around an ase slightly away from the axis of rotation of input shaft 2

is a front view of the drive mechanism of the input gear 201 of the first gear. On the left, the arms 401a and 401b drive the stops 501a and 501b in rotation only, but on the right, the resistive torque having decreased, the positions of the arms may have changed, and their end then also drives the stops 502a and 502b of the pinion d input 202 of the second speed which is not visible.

is a front view of the drive mechanism of the input gear 202 of the second gear. On the left, the arms 402a and 402b drive the stops 502a and 502b only, but on the right, the resistive torque having decreased, the positions of the arms may have changed, and their end then also drives the stops 503a and 503b of the input pinion 203 of the third gear which is not visible.

is a front view of the drive mechanism of the input pinion 203 of the third and last gear. The arms 403a and 403b drive the stops 503a and 503b.

is a perspective view of the drive mechanism of the input gear 202 of the second gear.

The present invention is a mechanical transmission called a stepped transmission comprising a plurality of means for transferring the movement of its input shaft 2 to its output shaft 3, called elementary transmissions each comprising an input which can be driven in rotation by said shaft. input and an output being able to drive said output shaft in rotation, at least two elementary transmissions being able to ensure this transfer of movement according to a different transmission ratio, characterized in that:
- At least one elementary transmission is provided with a clutch means called limiter 403 having the effect of mechanically disconnecting its output from its input to put it in the so-called disconnected configuration, or on the contrary to mechanically link its output to its input for the put in so-called connected configuration,
- At least one of said elementary transmissions comprises a unidirectional clutch means called freewheel 603 allowing two elementary transmissions of different transmission ratio to be simultaneously in a so-called connected configuration, while only one of them effectively ensures transferring motion from said input shaft to said output shaft,
- When an elementary transmission of rank N is in the connected configuration and effectively transfers the movement of said input shaft to said output shaft, a means called elementary transmission disengagement means that no elementary transmission of rank greater than N cannot be in a so-called connected configuration,
it being specified that above and below by “rank” of an elementary transmission is meant its order in the list of elementary transmissions whose transmission ratio is increasing, starting from the elementary transmission of rank 1 for that corresponding to the lowest transmission ratio also commonly called the "first gear".

Detailed description of the invention

The principle of the present invention consists in connecting an input shaft 2 to an output shaft 3 by a plurality of different means each having a different transmission ratio and in selecting the one of these means which is most suited to the situation.

The first advantage of this organization is that in the case where an elementary transmission consists of two toothed pinions cooperating with one another, these two toothed pinions remain permanently in cooperation, and that it is therefore not necessary to equip the transmission with synchros to avoid toothing conflicts.

The elementary transmissions each have a different transmission ratio, and the presence of freewheels means that two elementary transmissions of different transmission ratios can be engaged simultaneously. Thanks to the presence of freewheels, engaging an N-tier elementary transmission can without inconvenience automatically engage lower-tier elementary transmissions. As it is the elementary transmission of higher rank which rotates the output shaft at the highest angular speed, the presence of a freewheel has the effect that it is this elementary transmission and it alone which transmits the torque at the output shaft.

Input shaft 2 and output shaft 3 of the stepped transmission can be aligned. It suffices for this to provide a gear transmission of the output shaft 3 towards the axis of the input shaft 2, but when two elementary transmissions are associated in series, it is more convenient than the axis of rotation. of the output shaft of the second elementary transmission coincides with that of the input shaft of the first elementary transmission. In this case, it is particularly advantageous to provide the transmission with a one-way clutch allowing the frame supporting the elementary transmissions to rotate about the axis common to the input and output shafts of the transmission, in the engine direction, and to fit the stepped transmission with a torque or speed limiter on its output shaft 3 or on its input shaft 2, leaving the frame to rotate as long as this limiter, called general limiter, does not come into action. Thus, the stepped transmission can turn in direct drive as long as this limiter does not come into action.

The simplest version of the present invention (not shown) has only two elementary transmissions. One of them is a gear combining two pinions making it possible for example to reduce the reduction ratio to a value less than 1, and the other is the direct engagement between the input shaft 2 and the output shaft. 3 via a freewheel which is only connected when a limiter allows it. Such a transmission can have its input and output shafts aligned, so the assembly can rotate when in direct gear.

There is one embodiment of the present invention, in which the stepped transmission comprises a planetary gear, the input shaft of which rotates one of the three components. The term “planetary gearbox components” is understood hereinafter and below to be either the planet carrier fitted with its planet gear, the sun, and the ring gear, or a planet gear carrier fitted with planet wheels themselves comprising two toothed pinions of different diameters integral with each other. between them, associated either with two rings of different diameters, or with two suns of different diameters. These different types of planetary gears offer different well-known advantages, in particular as regards the direction of rotation of that of their components constituting the output shaft relative to the direction of rotation of that constituting their input shaft. In one of the possible configurations, the elementary transmission of the highest rank transmitting the movement is constituted by a clutch of the output shaft on the input shaft through its limiter. The highest tier elementary transmission puts the stepped transmission in direct gear, with the three components of the planetary gear rotating together at the same rotational speed. When the limiter of this first elementary transmission disengages this elementary transmission, the stepped transmission passes into a configuration in which the elementary transmission transmitting the movement is constituted by the operation of the epicyclic gear itself, the three components of which rotate at different speeds, a freewheel preventing one of the other components of the epicyclic gear from rotating in one of its two possible directions of rotation, so that the input shaft drives the output shaft at a different speed of rotation from that at which it would have been driven in the direct drive configuration described above, and / or in the reverse direction.

An elementary transmission can be engaged on the input shaft by any means controlled manually or by a computer, such as for example a limiter 403 consisting of a blocking element joining in rotation the input shaft and the input of. elementary transmission considered.

Advantageously, all the elementary transmissions include a torque or speed limiter, but this is not essential because one of them, for example the first gear, may not have one and be in permanent direct drive. . The advantage of providing the first gear with a torque or speed limiter is that this basic transmission can be used as a clutch.

A very simple solution is for the torque limiter to include a drive arm which directly or indirectly connects the input shaft to the output shaft of the elementary transmission to which it belongs when the torque to which the elementary transmission is subjected. considered exceeds a determined value or is less than a determined value. This method is known because it is used for certain breaking torque limiters. The permanent linkage of this drive arm may be at either end of its two ends, the one closest to its axis of rotation or the other.

By adjusting the position of the center of gravity of this drive arm, an elementary transmission can also be switched on and off depending on the speed of rotation of its input shaft or its output shaft. This is how the transmission in Figures 1 to 3 works.

During a mechanical overload, a drive arm flexes and its movable end ceases to cooperate with its mechanical connection means with the input shaft 2 or with the output shaft 3, as the case may be. In this case, the input pinion is no longer coupled to input shaft 2, while re-coupling is automatic. One can use rigid and articulated arms or flexible arms, or even arms which are both articulated and flexible. They may or may not have hooks as shown in Figures 1 to 3 and 5.

A training arm can be provided with an elastic return giving it several privileged intermediate resting positions, or notches. More generally, a limiter can be provided with an elastic return allowing it to be put into service or out of service only within a limited range of transmitted torque or speed as the case may be. This prevents two neighboring elementary transmissions from being selected alternately by switching too frequently from one to the other when their torque or speed limiter is close to the speed at which it is activated.

The connection between a drive arm and the pinion which it drives can be mechanical or magnetic. In general, all known types of torque or speed limiters can be used.

One of the elementary transmissions may not be provided with a freewheel, for example that corresponding to the last speed, the secondary pinion of which is always the one which rotates the fastest when the corresponding elementary transmission is connected. Likewise, one of the elementary transmissions may not be fitted with a limiter, such as for example the first gear which may remain connected permanently.

The clutch means constituting a limiter can advantageously be magnetic or electro-magnetic to avoid any mechanical conflict such as, for example, a toothing conflict.

The clutch means can also be a means connecting the input pinion of an elementary transmission with that of another elementary transmission. Those skilled in the art know how to design radially grooved surfaces which provide this type of connection when one of these surfaces is pressed onto another which is complementary to it. One can for example install a spring between such a surface connected in rotation to a primary pinion and a similar surface connected in rotation to the primary pinion of the adjacent elementary transmission, these springs being chosen so that the pressure on the first pinion drives the pinions in a determined order from a so-called rest position in which they are free to a so-called working position in which a pinion is secured to that of the elementary transmission of rank immediately below or immediately above, to rotate with it.

A recommended means, not shown, can consist for example in that a torque sensor constituted by a torsion bar mechanically brings about the approach or the distance of a primary gear from another which is adjacent to it, or of a means of securing between two pinions of the similar means which is adjacent thereto.

The volume in which this mechanism for securing two adjacent primary transmission gears is installed can be a ring, and the internal and external diameters of this ring can vary from one mechanism to the mechanism of the adjacent elementary transmission to have the necessary space. the operation of these mechanisms without expanding the corresponding primary gears. This makes it possible to limit the total size of the staged transmission.

A primary pinion passing from a free position to a working position can pass through an intermediate stage in which it is driven by friction, with the possibility of sliding providing the same effect as a gearbox synchro. In the case where the clutch means is magnetic or electro-magnetic, a primary gear may have magnets which attract each other when in the working position. The clutch function can thus be gradual and free from dust and wear. In an improved mode, the magnet or the electromagnet can have two possible positions so as not to be attracted by another in the rest position.

The limiters of a stepped transmission comprising means for securing in rotation an input pinion with that of an adjacent elementary transmission can thus form a cumulative clutch means engaging from 0 to N pinions in an order corresponding to increasing or decreasing values of the torque ratio of the elementary transmission to which they belong.

An improvement may consist in that the means for securing an input pinion with that of an adjacent primary transmission may also move the primary pinion along its axis of rotation. This movement can have the additional effect of stopping its cooperation with the secondary pinion of its elementary transmission when it is not the latter which transfers the movement of the input shaft to the output shaft, in order to decrease noise and improve performance. In this case, however, the possible toothing conflict must be managed when it comes to re-establishing this cooperation.

To simplify the construction, a limiter can also have the function of freewheeling. A primary pinion may for example include a part constituting the limiter or integral with it, separated from its teeth by a one-way clutch means such as a freewheel.

Both the limiter and the freewheel of an elementary transmission fitted with such components can just as easily be combined with its input pinion as with its output pinion.

In a preferred embodiment, a limiter disengages the elementary transmission to which it belongs when a condition called disengagement of the elementary transmission considered is fulfilled, this disengagement condition possibly being that the torque to which said elementary transmission is subjected is less than a value. predetermined, or that the speed of rotation to which it is subjected is lower or higher than a predetermined value.

Advantageously, the clutch neutralization means prevents an elementary transmission from being engaged as soon as the staged transmission is not subject to the condition of disengaging the elementary transmission in question.

A mechanical torque or speed limiter can be used to determine which elementary transmission transmits motion from input shaft 2 to output shaft 3.

When a limiter of an elementary transmission disconnects it, the conditions causing the disconnection cease because the torque undergone by this elementary transmission becomes zero, or because the speed becomes higher or lower than the threshold intended to cause the disconnection, depending on the case. The limiter in question must be prevented from reconnecting instantly for this reason alone.

Third gear disconnects after a certain torque is transmitted, and the second gear pinion takes over. In this case, the third gear must not be able to return to service, as it would disconnect immediately since there is insufficient torque for it to remain in service. The solution is that the third gear cannot reconnect once the second gear is connected and it is the third gear that transfers motion from the input shaft to the output shaft. It is therefore necessary that the position of the arm causing the rotation of the input pinion 202 prevents any cooperation between the arm 403 and the pinion 203. This rule is applied to the transmissions appearing in all the figures.

A particularly advantageous method is that several elementary transmissions include a limiter, and that the limiter of one of the elementary transmissions is mechanically linked to the limiter of another elementary transmission such that when this limiter connects a transmission, this simultaneously prevents the limiter. of the elementary transmission of higher rank to connect it. Such a mechanical connection between two limiters is asymmetrical, the connection of one of the two limiters and the fact that it is the elementary transmission to which it belongs which effectively transfers the movement from the input shaft to the output shaft. preventing the connection of the upper level elementary transmission limiter.

More generally, it is advantageous for a limiter to include a means called clutch neutralization means preventing an elementary transmission from being engaged, in the case where the stepped transmission is not subject to the condition of disengaging the elementary transmission. considered.

When the transmitted torque or the rotational speed, as the case may be, is close to the disengaging condition of an elementary transmission, the stepped transmission could switch an elementary transmission on and off at a rapid alternation rate, which is undesirable because it will cause jerking in the transmission and premature wear. To avoid this, it is desirable that the disengagement condition of an elementary transmission be different from a condition called the clutch condition which is that causing the clutch of the elementary transmission considered, this clutch condition possibly being that the torque to which the elementary transmission in question is subjected is greater than a predetermined value, or that the speed of rotation to which it is subjected is greater or less than a predetermined value, as the case may be.

An advantageous way to obtain this result is that a limiter or all of the limiters comprises a return means towards at least one equilibrium position associated with an elementary transmission, this return means favoring the maintenance of the clutch. elementary transmission considered even substantially beyond its conditions of engagement and disengagement.

We see in Figures 9 to 11 that the ends of the drive arms and the stops with which they cooperate to drive the input gears have a shape causing this balance. FIG. 12 makes it possible to distinguish a cylindrical protuberance 4020 at the end of the arm 402b which is housed in a cylindrical notch 5020 in the stop 502b in order to create a position of equilibrium of the second gear even when the disengagement condition is reached and slightly outdated. There are many other means that one skilled in the art can use to achieve a similar result, for example by giving the arms positions of intermediate balance through the use of springbacks or notches.

The position of a drive arm, when it ensures the commissioning of an input pinion, must not allow the drive arm of the adjacent elementary transmission to reach the position allowing the commissioning of this adjacent elementary transmission. In particular, it is particularly important to ensure that an elementary transmission must be able to switch to the engaged configuration when the adjacent lower elementary transmission is too.

In the event that the torque transmitted by the input shaft is irregular (bicycle crankset, crank, internal combustion engine, etc.), it may be advantageous to limit the possibilities of variation of the effect of a limiter at during one cycle of rotation of the input shaft. A preferred method for this is that the change of clutch-to-disengaged or disengaged-to-engaged configuration of the elementary transmission with which it is associated is slowed down by damping means.

It is possible to realize simplified versions of transmissions according to the present invention. For example, the functions of one-way clutch called freewheel and clutch means called limiter can be obtained by two toothed pinions whose teeth are asymmetrical to obtain the one-way clutch effect, and by an elastic deformation of a any part of the elementary transmission considered to obtain the effect of the so-called limiter clutch means. These two toothed pinions do not cooperate in one of the two possible directions of their respective rotations, and by playing on the flexibility of deformation of the toothed pinions, it is possible to favor the connection of an elementary transmission for a range of torque or speed of rotation. . This version is not shown.

To limit the shock undergone by a freewheel when connecting the elementary transmission with which it is associated, it is advantageous for any element of an elementary transmission to have the possibility of elastic deformation. FIG. 6 shows a helical spring 806, providing the mechanical connection between the toothing and the freewheel of the secondary pinion 303 which performs this function.

Another means of protecting the freewheel may consist in providing the output of an elementary transmission with a centrifugal clutch, which has the effect that it drives the output shaft only after it has been engaged by the limiter. .

The present invention makes it possible to produce automatic transmissions that do not use any electromechanical or computer device, but it can also be implemented using limiters comprising one or more actuators controlled electrically or by a computer. It is also possible to achieve a manual transmission by manually actuating each of the limiters or all of the limiters when the latter are mechanically connected.

We can of course assemble a very large number of elementary transmissions, and these elementary transmissions can be of different natures, connecting and disconnecting according to different parameters such as torque or speed, as a combination of the two or even manually or on computer control.

An elementary transmission can include several limiters with different characteristics assembled in series. The possibilities are therefore very numerous. This makes it possible to engage an elementary transmission based on a combination of manual or computerized controls, and transmitted rotational speed and torque parameters.

The great advantages of the present invention are that the change of transmission ratio can be fully automated depending on the torque transmitted and / or the speed of an input or output shaft, and that it is not necessary to provide such a transmission with synchromes or even a clutch, as will be seen below.

A torque or speed limiter can be provided with a so-called sensitivity adjustment means making it possible to vary the value of the torque or of the speed causing the connection and disconnection of an elementary transmission. This means can modify the operating rules of a single limiter as well or be common to several limiters as shown in Figures 1 to 3 and 6.

Figure 4 shows a drive arm synchronization mechanism 401b and 401c. Those skilled in the art can use such a mechanism to move not three arms each supporting a support of an elastic link 804 as shown in Figure 6, but a greater number of such supports so that they form together a path remaining substantially circular for all the positions of the drive arms (version not shown). The tension of the elastic link 804 can then easily be changed in real time by the user, either with a cable control or by the use of electrical means which can be controlled by computer. In the case of an automobile, for example, the tension of this elastic link can be changed by pressing the accelerator pedal.

There are many other ways available to those skilled in the art to vary the effect of torque or shaft speed on a limiter, as well as its elastic return. This is particularly easy when the clutch means is a means joining in rotation the input pinion of an elementary transmission with that of one or more other elementary transmissions, because the elastic return can then be a simple spring located in the axis of rotation of the primary shaft (version not shown). The tension or compression of this spring can indeed easily be changed during the rotation of the shaft and pinions.

Such an adjustment means can also make it possible to disconnect an elementary transmission, which thus gives a disengaging function to the transmission. It should be noted that this clutch operates without friction, so with virtually no loss of energy or wear or dust.

Such an adjustment means can also, indirectly, make it possible to manually or by computer select the connection or disconnection of an elementary transmission, and therefore to change the transmission ratio on command.

This improvement is also useful because it makes it possible to equip the transmission with a reverse gear, which can thus be disengaged when the transmission is operating in forward gear. Symmetrically, the elementary transmission (s) corresponding to forward gear can be disengaged when the elementary transmission corresponding to reverse gear is put into service.

When driven by a heat engine always rotating in the same direction, an elementary transmission ensuring reverse gear differs from an elementary transmission ensuring forward gear by the nature of its gears which must cause a change of direction relative to that an elementary transmission ensuring forward travel, but when the input shaft 2 is driven in rotation by an electric motor which can easily be rotated in one direction or the other, an elementary transmission ensuring operation rear only differs from an elementary transmission ensuring forward travel by the authorized direction of rotation of its one-way clutch.

In an improved version shown in FIG. 5, at least one of said elementary transmissions (here the first speed) has a transmission ratio which varies as a function of the torque to which it is subjected or of its speed of rotation. There are many ways of carrying out such transmissions, including those described in the aforementioned documents PCT-FR-2019-000030 and FR1870485.

It is also possible to achieve with the invention dual clutch gearboxes like the one shown in Figure 5. Such a transmission comprises two sets of elementary transmissions corresponding to so-called even and odd transmission ratios as is widely known. Each of these elementary transmissions transmits its movement to a clutch disc, respectively 801 and 802. These clutch discs cooperate alternately with the output shaft 3 of the assembly via a third clutch disc 800. The advantage is to avoid shocks during the commissioning of a freewheel, since the latter is commissioned before ensuring the transmission of torque to the output shaft 3. This arrangement is therefore particularly suitable for transmissions. power.

Another, simpler method of avoiding shocks during the commissioning of a freewheel may consist in providing any element of an elementary transmission 806 with the possibility of elastic deformation. The part of a toothed pinion comprising the teeth may for example shift angularly from the central part of this pinion under the force of a torque transferred by the pinion as shown in FIG. 6. When an elementary transmission does not transfer the torque, the pinion considered is thus in the rest configuration, and it only gradually passes into the working position when the elementary transmission considered is connected. Such a resilient toothed pinion may equally well be an input pinion or an output pinion.

Special provisions and combinations

A transmission according to the invention can also be associated in series with any other type of manual or automatic gearbox. In particular, two transmissions can be combined according to the invention, and one of them can be manual while the other can be automatic. The manual transmission can allow the user to choose an operating mode ranging for example for a bicycle or a car from "walking" to "sport" while the automatic transmission then adapts the transmission ratio to the conditions encountered such as the nature of the vehicle. terrain for example.

Two transmissions according to the invention or of other types can be associated in parallel, sharing the same output shaft and having input shafts driven in rotation by different means, such as for example a crankset and a motor in the case electric bikes. When a transmission according to the invention includes an epicyclic gear, one of the components of this gear can receive energy from one power source and the other from another, as is known.

The transmissions according to the invention can also be assembled in parallel to drive two wheels on the same axle without the need for a differential.

A series assembly of staged transmissions according to the invention makes it possible to have a number of transmission ratios which is the result of the multiplication of the numbers of elementary transmissions of each of the staged transmissions.

All the arrangements and combinations described in the aforementioned document PCT-FR-2019-000030 can obviously be implemented within the framework of the present invention, including in particular when an elementary transmission has a continuously variable transmission ratio:
- blocking and unblocking of the variation in the radius of gyration of the crankpin,
- limitation of the variation during part of the cycle,
- modification of the orientation of a rack,
- the implementation of combined forms between rack and sector,
- the use of a double rack operating on the outward and return routes,
- the use of interchangeable racks,
- transmission reversal,
- blocking of the transmission,
- limitation of the stroke of the rack and / or the sector,
- the elastic return at the end of the stroke of a connecting element,
- the use of a motor lever,
and in all cases:
- limitation of the elastic deformation of a connecting element,
- the damping of any elastic deformation of a connecting element,
- the balancing of a transmission by arranging several elementary transmissions symmetrically with respect to the axis of the input shaft and / or of the output shaft,
- reciprocal operation, making it possible to have an engine brake or to start an internal combustion engine,
- energy storage and braking,
- and the use of a separate launcher.

The invention is also a machine provided with a transmission according to the invention or transmitting its power by such a transmission, or set in motion by such a transmission.

It is also the method of transmitting motion from an input shaft 2 to an output shaft 3 through the use of a mechanical transmission according to the invention.

Applications

The main applications are as follows:
- stepped gearboxes with fixed ratios, manual or automatic speed change, in particular those whose transmission ratio changes automatically according to the resistive torque and / or the engine speed, and / or the speed of rotation of the engine. 'output shaft,
- continuously variable gear transmissions,
- centrifugal clutches without energy loss,
- torque limiters,
- the transfer of power to a plurality of driving wheels by a plurality of transmissions according to the invention, replacing the differentials,
- the combination of several energy sources, each being connected to the same output shaft by a transmission according to the invention, or by an elementary transmission of a transmission according to the invention,
- electric motors provided with a transmission according to the invention to withstand any torque greater than that supplied by the motor during its normal operation, for example that which is necessary for starting or in the event of mechanical overload,
- energy recovery when braking, by coupling the wheels to an energy storage means, by varying the transmission ratio to dose the stored energy and therefore the amount of braking,
- real-time adaptation of the transmission ratio of wind turbines and tidal turbines to the optimum speed of their electric generator
- energy storage in flywheels of industrial machines and toys,
- the propulsion of bicycles and other vehicles or machines driven by a crankset or cranks,
- the automobile,
- winches, jacks and winches whose transmission ratio automatically adapts to the resistive torque,
- rotating tools.

Claims (1)

Mechanical transmission called stepped transmission comprising a plurality of means for transferring movement from its input shaft (2) to its output shaft (3), called elementary transmissions each comprising an input which can be driven in rotation by said input shaft and an output capable of driving said input shaft in rotation, at least two elementary transmissions capable of ensuring this transfer of movement according to a different transmission ratio, characterized in that:
- At least one elementary transmission is provided with a clutch means called limiter (403) having the effect of mechanically disconnecting its output from its input to put it in the so-called disconnected configuration, or on the contrary to mechanically link its output to its input to put it in a so-called connected configuration,
- at least one of said elementary transmissions comprises a one-way clutch means called freewheel (603) allowing two elementary transmissions of different transmission ratio to be simultaneously in a so-called connected configuration, while only one of them effectively transfers movement from said input shaft to said output shaft,
- When an elementary transmission of rank N is in the connected configuration and effectively transfers the movement of said input shaft to said output shaft 3, a means called elementary transmission disengagement means that no elementary transmission of higher rank to N cannot be in a so-called connected configuration,
it being specified that one understands above and below by rank "of an elementary transmission its order in the list of elementary transmissions of which the transmission ratio is increasing, starting from the elementary transmission of rank 1 for that corresponding to the lowest gear ratio also commonly referred to as "first gear".